Abstract
The correlation between the extractable activities of three key enzymes of assimilatory sulfate reduction and the in vivo incorporation of (35)SO(4) (2-) into amino acids, proteins, and sulfolipids was investigated from greening to senescence in primary leaves of beans (Phaseolus vulgaris L.). The total extractable activity of ATP sulfurylase (EC 2.7.7.4) and of adenosine 5'-phosphosulfate sulfotransferase reached a maximum in the leaves of approximately 7- and 11-day-old seedlings, respectively. During senescence, there was a decrease in both enzyme activities. After approximately 17 days, no appreciable activities remained. In contrast, total O-acetyl-l-serine sulfhydrylase (EC 4.3.99.8) activity decreased to only approximately 50% of the maximal value during the same period. The in vivo incorporation of (35)SO(4) (2-) into amino acid and protein fractions showed a time-course similar to that of the total extractable adenosine 5'-phosphosulfate sulfotransferase activity. Both cysteine and sulfate markedly decreased during senescence. The total extractable activity of ribulosebisphosphate carboxylase (EC 4.1.1.39) was maximal in the primary leaves of 13-day-old seedlings, and approximately 40% of this value was still detectable after 17 days. Taken together with results from the literature, these results show that assimilatory sulfate reduction in primary leaves of P. vulgaris L. stops before CO(2) and nitrate assimilation.
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Claims 9
Claim · model-written summary
ATP sulfurylase activity peaked in leaves of approximately 7-day-old bean seedlings.
Verbatim
e0“The total extractable activity of ATP sulfurylase (EC 2.7.7.4) and of adenosine 5'-phosphosulfate sulfotransferase reached a maximum in the leaves of approximately 7- and 11-day-old seedlings, respectively”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Adenosine 5-phosphosulfate sulfotransferase activity peaked at about 11 days.
Verbatim
e0“The total extractable activity of ATP sulfurylase (EC 2.7.7.4) and of adenosine 5'-phosphosulfate sulfotransferase reached a maximum in the leaves of approximately 7- and 11-day-old seedlings, respectively”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Both enzyme activities declined during senescence and were nearly absent after 17 days.
Verbatim
e0“During senescence, there was a decrease in both enzyme activities. After approximately 17 days, no appreciable activities remained”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
O-acetyl-l-serine sulfhydrylase activity declined to about 50% of its maximum.
Verbatim
e0“total O-acetyl-l-serine sulfhydrylase (EC 4.3.99.8) activity decreased to only approximately 50% of the maximal value”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Sulfate incorporation into amino acids and protein followed the sulfotransferase activity time course.
Verbatim
e0“The in vivo incorporation of (35)SO(4) (2-) into amino acid and protein fractions showed a time-course similar to that of the total extractable adenosine 5'-phosphosulfate sulfotransferase activity”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Cysteine and sulfate decreased markedly during senescence.
Verbatim
e0“Both cysteine and sulfate markedly decreased during senescence”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Ribulosebisphosphate carboxylase activity peaked at 13 days.
Verbatim
e0“The total extractable activity of ribulosebisphosphate carboxylase (EC 4.1.1.39) was maximal in the primary leaves of 13-day-old seedlings”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
About 40% of peak ribulosebisphosphate carboxylase activity remained after 17 days.
Verbatim
e0“approximately 40% of this value was still detectable after 17 days”
t0“Regulation of Sulfate Assimilation in Plants”
e1“beans (Phaseolus vulgaris L.)”
Claim · model-written summary
Assimilatory sulfate reduction stops before carbon dioxide and nitrate assimilation in primary bean leaves.
- Taxon
- P. vulgaris L.
Phaseolus vulgarise0 - Organ / stage
- primary leavese0
- Outcome
- assimilatory sulfate reductione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“assimilatory sulfate reduction in primary leaves of P. vulgaris L. stops before CO(2) and nitrate assimilation”